ASoC: stm32: add DFSDM DAI support

Add driver to handle DAI interface for PDM microphones connected
to Digital Filter for Sigma Delta Modulators IP.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

3 files changed, 361 insertions, 0 deletions

diff --git a/sound/soc/stm/Kconfig b/sound/soc/stm/Kconfig
index 3398e6c57f37..a78f7700d489 100644
--- a/sound/soc/stm/Kconfig
+++ b/sound/soc/stm/Kconfig
@@ -28,4 +28,15 @@ config SND_SOC_STM32_SPDIFRX
         help
           Say Y if you want to enable S/PDIF capture for STM32
 
+config SND_SOC_STM32_DFSDM
+        tristate "SoC Audio support for STM32 DFSDM"
+        depends on (ARCH_STM32 && OF && STM32_DFSDM_ADC) || COMPILE_TEST
+        depends on SND_SOC
+        select SND_SOC_GENERIC_DMAENGINE_PCM
+        select SND_SOC_DMIC
+        select IIO_BUFFER_CB
+        help
+          Select this option to enable the STM32 Digital Filter
+          for Sigma Delta Modulators (DFSDM) driver used
+          in various STM32 series for digital microphone capture.
 endmenu
diff --git a/sound/soc/stm/Makefile b/sound/soc/stm/Makefile
index 5b7f0fab0bd6..3143c0b47042 100644
--- a/sound/soc/stm/Makefile
+++ b/sound/soc/stm/Makefile
@@ -13,3 +13,6 @@ obj-$(CONFIG_SND_SOC_STM32_I2S) += snd-soc-stm32-i2s.o
 # SPDIFRX
 snd-soc-stm32-spdifrx-objs := stm32_spdifrx.o
 obj-$(CONFIG_SND_SOC_STM32_SPDIFRX) += snd-soc-stm32-spdifrx.o
+
+#DFSDM
+obj-$(CONFIG_SND_SOC_STM32_DFSDM) += stm32_adfsdm.o
diff --git a/sound/soc/stm/stm32_adfsdm.c b/sound/soc/stm/stm32_adfsdm.c
new file mode 100644
index 000000000000..af50891983c6
--- /dev/null
+++ b/sound/soc/stm/stm32_adfsdm.c
@@ -0,0 +1,347 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file is part of STM32 DFSDM ASoC DAI driver
+ *
+ * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
+ * Authors: Arnaud Pouliquen <arnaud.pouliquen@st.com>
+ *          Olivier Moysan <olivier.moysan@st.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/consumer.h>
+#include <linux/iio/adc/stm32-dfsdm-adc.h>
+
+#include <sound/pcm.h>
+#include <sound/soc.h>
+
+#define STM32_ADFSDM_DRV_NAME "stm32-adfsdm"
+
+#define DFSDM_MAX_PERIOD_SIZE   (PAGE_SIZE / 2)
+#define DFSDM_MAX_PERIODS       6
+
+struct stm32_adfsdm_priv {
+        struct snd_soc_dai_driver dai_drv;
+        struct snd_pcm_substream *substream;
+        struct device *dev;
+
+        /* IIO */
+        struct iio_channel *iio_ch;
+        struct iio_cb_buffer *iio_cb;
+        bool iio_active;
+
+        /* PCM buffer */
+        unsigned char *pcm_buff;
+        unsigned int pos;
+};
+
+static const struct snd_pcm_hardware stm32_adfsdm_pcm_hw = {
+        .info = SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER |
+            SNDRV_PCM_INFO_PAUSE,
+        .formats = SNDRV_PCM_FMTBIT_S32_LE,
+
+        .rate_min = 8000,
+        .rate_max = 32000,
+
+        .channels_min = 1,
+        .channels_max = 1,
+
+        .periods_min = 2,
+        .periods_max = DFSDM_MAX_PERIODS,
+
+        .period_bytes_max = DFSDM_MAX_PERIOD_SIZE,
+        .buffer_bytes_max = DFSDM_MAX_PERIODS * DFSDM_MAX_PERIOD_SIZE
+};
+
+static void stm32_adfsdm_shutdown(struct snd_pcm_substream *substream,
+                                  struct snd_soc_dai *dai)
+{
+        struct stm32_adfsdm_priv *priv = snd_soc_dai_get_drvdata(dai);
+
+        if (priv->iio_active) {
+                iio_channel_stop_all_cb(priv->iio_cb);
+                priv->iio_active = false;
+        }
+}
+
+static int stm32_adfsdm_dai_prepare(struct snd_pcm_substream *substream,
+                                    struct snd_soc_dai *dai)
+{
+        struct stm32_adfsdm_priv *priv = snd_soc_dai_get_drvdata(dai);
+        int ret;
+
+        ret = iio_write_channel_attribute(priv->iio_ch,
+                                          substream->runtime->rate, 0,
+                                          IIO_CHAN_INFO_SAMP_FREQ);
+        if (ret < 0) {
+                dev_err(dai->dev, "%s: Failed to set %d sampling rate\n",
+                        __func__, substream->runtime->rate);
+                return ret;
+        }
+
+        if (!priv->iio_active) {
+                ret = iio_channel_start_all_cb(priv->iio_cb);
+                if (!ret)
+                        priv->iio_active = true;
+                else
+                        dev_err(dai->dev, "%s: IIO channel start failed (%d)\n",
+                                __func__, ret);
+        }
+
+        return ret;
+}
+
+static int stm32_adfsdm_set_sysclk(struct snd_soc_dai *dai, int clk_id,
+                                   unsigned int freq, int dir)
+{
+        struct stm32_adfsdm_priv *priv = snd_soc_dai_get_drvdata(dai);
+        ssize_t size;
+        char str_freq[10];
+
+        dev_dbg(dai->dev, "%s: Enter for freq %d\n", __func__, freq);
+
+        /* Set IIO frequency if CODEC is master as clock comes from SPI_IN */
+
+        snprintf(str_freq, sizeof(str_freq), "%d\n", freq);
+        size = iio_write_channel_ext_info(priv->iio_ch, "spi_clk_freq",
+                                          str_freq, sizeof(str_freq));
+        if (size != sizeof(str_freq)) {
+                dev_err(dai->dev, "%s: Failed to set SPI clock\n",
+                        __func__);
+                return -EINVAL;
+        }
+        return 0;
+}
+
+static const struct snd_soc_dai_ops stm32_adfsdm_dai_ops = {
+        .shutdown = stm32_adfsdm_shutdown,
+        .prepare = stm32_adfsdm_dai_prepare,
+        .set_sysclk = stm32_adfsdm_set_sysclk,
+};
+
+static const struct snd_soc_dai_driver stm32_adfsdm_dai = {
+        .capture = {
+                    .channels_min = 1,
+                    .channels_max = 1,
+                    .formats = SNDRV_PCM_FMTBIT_S32_LE,
+                    .rates = (SNDRV_PCM_RATE_8000 | SNDRV_PCM_RATE_16000 |
+                              SNDRV_PCM_RATE_32000),
+                    },
+        .ops = &stm32_adfsdm_dai_ops,
+};
+
+static const struct snd_soc_component_driver stm32_adfsdm_dai_component = {
+        .name = "stm32_dfsdm_audio",
+};
+
+static int stm32_afsdm_pcm_cb(const void *data, size_t size, void *private)
+{
+        struct stm32_adfsdm_priv *priv = private;
+        struct snd_soc_pcm_runtime *rtd = priv->substream->private_data;
+        u8 *pcm_buff = priv->pcm_buff;
+        u8 *src_buff = (u8 *)data;
+        unsigned int buff_size = snd_pcm_lib_buffer_bytes(priv->substream);
+        unsigned int period_size = snd_pcm_lib_period_bytes(priv->substream);
+        unsigned int old_pos = priv->pos;
+        unsigned int cur_size = size;
+
+        dev_dbg(rtd->dev, "%s: buff_add :%p, pos = %d, size = %zu\n",
+                __func__, &pcm_buff[priv->pos], priv->pos, size);
+
+        if ((priv->pos + size) > buff_size) {
+                memcpy(&pcm_buff[priv->pos], src_buff, buff_size - priv->pos);
+                cur_size -= buff_size - priv->pos;
+                priv->pos = 0;
+        }
+
+        memcpy(&pcm_buff[priv->pos], &src_buff[size - cur_size], cur_size);
+        priv->pos = (priv->pos + cur_size) % buff_size;
+
+        if (cur_size != size || (old_pos && (old_pos % period_size < size)))
+                snd_pcm_period_elapsed(priv->substream);
+
+        return 0;
+}
+
+static int stm32_adfsdm_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+        struct snd_soc_pcm_runtime *rtd = substream->private_data;
+        struct stm32_adfsdm_priv *priv =
+                snd_soc_dai_get_drvdata(rtd->cpu_dai);
+
+        switch (cmd) {
+        case SNDRV_PCM_TRIGGER_START:
+        case SNDRV_PCM_TRIGGER_RESUME:
+                priv->pos = 0;
+                return stm32_dfsdm_get_buff_cb(priv->iio_ch->indio_dev,
+                                               stm32_afsdm_pcm_cb, priv);
+        case SNDRV_PCM_TRIGGER_SUSPEND:
+        case SNDRV_PCM_TRIGGER_STOP:
+                return stm32_dfsdm_release_buff_cb(priv->iio_ch->indio_dev);
+        }
+
+        return -EINVAL;
+}
+
+static int stm32_adfsdm_pcm_open(struct snd_pcm_substream *substream)
+{
+        struct snd_soc_pcm_runtime *rtd = substream->private_data;
+        struct stm32_adfsdm_priv *priv = snd_soc_dai_get_drvdata(rtd->cpu_dai);
+        int ret;
+
+        ret =  snd_soc_set_runtime_hwparams(substream, &stm32_adfsdm_pcm_hw);
+        if (!ret)
+                priv->substream = substream;
+
+        return ret;
+}
+
+static int stm32_adfsdm_pcm_close(struct snd_pcm_substream *substream)
+{
+        struct snd_soc_pcm_runtime *rtd = substream->private_data;
+        struct stm32_adfsdm_priv *priv =
+                snd_soc_dai_get_drvdata(rtd->cpu_dai);
+
+        snd_pcm_lib_free_pages(substream);
+        priv->substream = NULL;
+
+        return 0;
+}
+
+static snd_pcm_uframes_t stm32_adfsdm_pcm_pointer(
+                                            struct snd_pcm_substream *substream)
+{
+        struct snd_soc_pcm_runtime *rtd = substream->private_data;
+        struct stm32_adfsdm_priv *priv =
+                snd_soc_dai_get_drvdata(rtd->cpu_dai);
+
+        return bytes_to_frames(substream->runtime, priv->pos);
+}
+
+static int stm32_adfsdm_pcm_hw_params(struct snd_pcm_substream *substream,
+                                      struct snd_pcm_hw_params *params)
+{
+        struct snd_soc_pcm_runtime *rtd = substream->private_data;
+        struct stm32_adfsdm_priv *priv =
+                snd_soc_dai_get_drvdata(rtd->cpu_dai);
+        int ret;
+
+        ret =  snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params));
+        if (ret < 0)
+                return ret;
+        priv->pcm_buff = substream->runtime->dma_area;
+
+        return iio_channel_cb_set_buffer_watermark(priv->iio_cb,
+                                                   params_period_size(params));
+}
+
+static int stm32_adfsdm_pcm_hw_free(struct snd_pcm_substream *substream)
+{
+        snd_pcm_lib_free_pages(substream);
+
+        return 0;
+}
+
+static struct snd_pcm_ops stm32_adfsdm_pcm_ops = {
+        .open           = stm32_adfsdm_pcm_open,
+        .close          = stm32_adfsdm_pcm_close,
+        .hw_params      = stm32_adfsdm_pcm_hw_params,
+        .hw_free        = stm32_adfsdm_pcm_hw_free,
+        .trigger        = stm32_adfsdm_trigger,
+        .pointer        = stm32_adfsdm_pcm_pointer,
+};
+
+static int stm32_adfsdm_pcm_new(struct snd_soc_pcm_runtime *rtd)
+{
+        struct snd_pcm *pcm = rtd->pcm;
+        struct stm32_adfsdm_priv *priv =
+                snd_soc_dai_get_drvdata(rtd->cpu_dai);
+        unsigned int size = DFSDM_MAX_PERIODS * DFSDM_MAX_PERIOD_SIZE;
+
+        return snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV,
+                                                     priv->dev, size, size);
+}
+
+static void stm32_adfsdm_pcm_free(struct snd_pcm *pcm)
+{
+        struct snd_pcm_substream *substream;
+        struct snd_soc_pcm_runtime *rtd;
+        struct stm32_adfsdm_priv *priv;
+
+        substream = pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream;
+        if (substream) {
+                rtd = substream->private_data;
+                priv = snd_soc_dai_get_drvdata(rtd->cpu_dai);
+
+                snd_pcm_lib_preallocate_free_for_all(pcm);
+        }
+}
+
+static struct snd_soc_platform_driver stm32_adfsdm_soc_platform = {
+        .ops            = &stm32_adfsdm_pcm_ops,
+        .pcm_new        = stm32_adfsdm_pcm_new,
+        .pcm_free       = stm32_adfsdm_pcm_free,
+};
+
+static const struct of_device_id stm32_adfsdm_of_match[] = {
+        {.compatible = "st,stm32h7-dfsdm-dai"},
+        {}
+};
+MODULE_DEVICE_TABLE(of, stm32_adfsdm_of_match);
+
+static int stm32_adfsdm_probe(struct platform_device *pdev)
+{
+        struct stm32_adfsdm_priv *priv;
+        int ret;
+
+        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+        if (!priv)
+                return -ENOMEM;
+
+        priv->dev = &pdev->dev;
+        priv->dai_drv = stm32_adfsdm_dai;
+
+        dev_set_drvdata(&pdev->dev, priv);
+
+        ret = devm_snd_soc_register_component(&pdev->dev,
+                                              &stm32_adfsdm_dai_component,
+                                              &priv->dai_drv, 1);
+        if (ret < 0)
+                return ret;
+
+        /* Associate iio channel */
+        priv->iio_ch  = devm_iio_channel_get_all(&pdev->dev);
+        if (IS_ERR(priv->iio_ch))
+                return PTR_ERR(priv->iio_ch);
+
+        priv->iio_cb = iio_channel_get_all_cb(&pdev->dev, NULL, NULL);
+        if (IS_ERR(priv->iio_cb))
+                return PTR_ERR(priv->iio_ch);
+
+        ret = devm_snd_soc_register_platform(&pdev->dev,
+                                             &stm32_adfsdm_soc_platform);
+        if (ret < 0)
+                dev_err(&pdev->dev, "%s: Failed to register PCM platform\n",
+                        __func__);
+
+        return ret;
+}
+
+static struct platform_driver stm32_adfsdm_driver = {
+        .driver = {
+                   .name = STM32_ADFSDM_DRV_NAME,
+                   .of_match_table = stm32_adfsdm_of_match,
+                   },
+        .probe = stm32_adfsdm_probe,
+};
+
+module_platform_driver(stm32_adfsdm_driver);
+
+MODULE_DESCRIPTION("stm32 DFSDM DAI driver");
+MODULE_AUTHOR("Arnaud Pouliquen <arnaud.pouliquen@st.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" STM32_ADFSDM_DRV_NAME);